Introduction of Oracle PL/SQL cursor

a definition

A cursor, also called a cursor, is a Result Set.

 

two grammar

CURSOR cursor name [(parameter name data type [, parameter name data type]...)]

IS SELECT statement;

 

Three cursor usage

1. Define the cursor

cursor c1 is select ename from emp;

2. Open the cursor to execute the query

open c1;

3. Take a line to a variable

fetch c1 into pename;

 

4. Close close to release resources

close c1;

 

Four examples

1. Demand

Use the cursor to query the employee's name and salary, and print it.

2. Code

1. --查询并打印员工的姓名和薪水
2. /*
3. 1.光标属性
4. %found %notfound
5. */
6. set serveroutput on
8. declare
9. --定义一个光标
10. cursor cemp isselect ename,sal from emp;
11. --为光标定义对应的变量
12. pename emp.ename%type;
13. psal emp.sal%type;
14. begin
15. --打开光标
16. open cemp;
17. loop
18. --取一条记录
19. fetch cemp into pename,psal;
20. --思考：1循环什么时候退出？2fetch不一定能取到记录
21. --exitwhen没有取到记录
22. exitwhen cemp%notfound;
23. dbms_output.put_line(pename||'的薪水是'||psal);
24. end loop;
25. --关闭光标
26. close cemp;
27. end;
28. /

3. Running results

SMITH's salary is 800

ALLEN's salary is 1600

WARD salary is 1250

JONES' salary is 2975

MARTIN's salary is 1250

BLAKE's salary is 2850

CLARK's salary is 2450

SCOTT's salary is 3000

King's salary is 5000

TURNER's salary is 1500

ADAMS salary is 1100

JAMES' salary is 950

FORD's salary is 3000

MILLER's salary is 1300

 

PL/SQL procedure completed successfully.